The invention relates to a process and apparatus for the reclamation and repeated use of waste water which previously had been subjected to oil contamination.
In systems manipulating different heavy oils (e.g. heating oil, residual asphalt and the like) waster water from the steam which previously was used for, respectively, racking-off the oil, storage, transport, warming and heating of the oil, in order to protect the boiler was led together with leaking oil into the purifying system for purifying the oil-contaminated waste water after the oil is separated it is recirculated into the storage space, while the waste water, being properly cleared in accordance with prevailing technical circumstances but still containing a certain quantity of oil contamination and accordingly, not being suitable for the use as feedwater for the boiler, is discharged into an above-ground recipient (e.g. a brook, a river and the like). In such a manner the heat content of the waste water which is at a temperature of about 150.degree. C. is completely lost. Instead of using the discharged waste water as a feedwater for the boiler softened water is used increasing costs, because considerable energy consumption is required to soften and heat it. By observing the relevant specifications and standards certain procedures are possible to follow for the recirculation of the waste water arising, in particular, during the basic heating of tanks, in the course of pre-heating the exhaust heat-exchanger of the tanks, or the accompanying heating of other apparatus. The minor part of the waste water results from heating the filters and oil-heating heat-exchangers. However, recirculation of this type of waste water is not permitted by the relevant standards. The pre-requisite of the repeated use of the waste water of oil-manipulating systems is, that under no circumstances can water with oil surpassing the level prescribed in the standard be recirculated into the boiler or any other similar equipment.
Accordingly, the object of the invention is to develop a process and an apparatus which enables the repeated use of the waste water from oil manipulating systems in such a manner that the admission of the oil-contaminated waste water into the feedwater of the heating system is prevented in a reliable manner, and simultaneously the waste water which is suitable for further use is led to the place of utilization.